Posted on 02/09/2009 8:59:10 AM PST by SunkenCiv
Based on chemical signatures inside sedimentary rocks, Love and colleagues think the sponges likely grew in colonies that blanketed areas of the ocean floor. Back then the supercontinent Rodinia, which had been Earth's dominant landmass for at least 350 million years, was in the process of breaking up, and the climate was extremely cold worldwide. Sponges evolved in shallow ocean basins, because the deeper seas did not yet contain oxygen, a necessity for almost all life. Although the environment was harsh at this time -- about a hundred million years before the evolutionary growth spurt known as the Cambrian explosion -- a lack of predators made life easier for the sponges... Love and colleagues were able to date the sea sponges because the animals' chemical traces were found in rocks beneath glacial deposits from an ice age that ended about 635 million years ago. The scientists cut away the outer surfaces of the rock, cleaned the remaining core with solvents, and crushed what was left behind into a powder that could be chemically separated into its component parts... Kevin Peterson of Dartmouth College and his colleagues had independently hypothesized that sponges lived about 650 million years ago based on biological clues in the genes of modern sponges.
(Excerpt) Read more at news.nationalgeographic.com ...
Fish glide past barrel sponges on a coral reef in an undated photo. Sea sponges were thriving about a hundred million years before the evolutionary growth spurt that gave rise to modern animals, according to a February 2009 study. Fossil steroids produced by the sponges are now the oldest known fossil evidence of animal life, the study says. [Photograph by Commander William Harrigan/Florida Keys National Marine Sanctuary/NOAA]
I think Spongebob would feel good about this.
Oh how far we’ve evolved. From sea sponges to democrats.
When Spongebob ruled the sea!
I dodn’t know that sponges like Oboma were that old.
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IOW, animal life will never be *wiped out*. |
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Note to researchers: you shouldn't have sampled the precambrian rocks downslope from Barry Bond's septic tank.
This far removed, they will have to give all of us some time to allow this to soak in...
New Madrid fault and Earthquake prone region considered at high risk today.
The New Madrid Seismic Zone is made up of reactivated faults that formed when North America began to split or rift apart during the breakup of the supercontinent Rodinia in the Neoproterozoic Era (about 750 million years ago). The resulting rift system failed but remained as an aulacogen (a scar or zone of weakness). The area was then flooded by an ancient ocean, depositing layers of sediment on the rift.
http://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone
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A reconstruction of the supercontinent Rodinia 100 million years after breaking apart. Note the position of Alaska and the western margin of North America (labeled “Laurentia”). The giant continent split along the eastern margin of what is today Washington State. The future Pacific Northwest was a tectonically quiet, passive continental margin. (Image: Christopher Scotese, Paleomap Project)
http://www.washington.edu/burkemuseum/geo_history_wa/Dance%20of%20the%20Giant%20Continents.htm
It must have been a major shock when Rodinia broke up, but apparently the sponges were able to absorb it. /rimshot
Thanks ETL!
...and to filter through...
I see you’ve come not to praise but to Barry Bonds... /rimshot
A blot here, a blot there, and we still end up with sponges!~
These suckers don't turn into dinosaurs.
Well, we ought to be grateful for it. Think how much higher the ocean levels would be if it weren’t for all those sponges absorbing the water.
;^)
Unless the derivatives compete with the originals, into a deathmatch, the originals needn't go extinct.
Homo sapiens largely eliminated Homo neanderthalis
/rimshot!
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